A building collapse at a garment factory in Bangladesh has left at least 100 people dead and injured a thousand more. This is the second disaster at a Bangladeshi garment factory in less than six months.

The report on supplier responsibility from Apple indicates progress on working conditions and excessive overtime requirements at the tech giant's Chinese suppliers, including its largest supplier, Foxconn. But the report also revealed one supplier was employing child workers.

Nearly a quarter of a billion Chinese workers relocated from the country's interior to the factory towns on the coast in one of the largest human migration the planet has ever known. Now, 20 years later, the great migration is drawing to a close.